AB0558 PREVALENCE OF LATENT TUBERCULOSIS INFECTION AND ITS ASSOCIATIONS WITH CLINICAL AND SEROLOGICAL PARAMETERS IN SYSTEMIC LUPUS ERYTHEMATOSUS
Authors: G. Ms, P. B. Narasimhan, C. Kavadichanda, A. Gopal, D. Bairwa, M. M. Thabah, S. Sarkar, V. Negi
Journal: Annals of the Rheumatic Diseases (2022)

Background Systemic Lupus Erythematosus (SLE) and Tuberculosis are complicatedly related and studies have shown increased risk of TB in SLE. Studies of Latent TB and SLE are inadequate. This study intended to assess the prevalence of latent TB and its association with disease parameters in SLE. Objectives To assess the prevalence of latent TB in patients with SLE. To investigate the demographics and clinical characteristics in patients with SLE and concomitant latent TB compared to those without. Methods This is a single center cross sectional study. 124 adult patients with SLE without past h/o TB were recruited. SLE demography, disease activity indices, autoantibody profile and steroid use were noted. Presence of Latent TB infection was assessed in all patients based on the IFN-g release assay (TB-IGRA). Based on the results of IGRA, SLE cases were divided into 2 groups-IGRA positive and IGRA negative. The collected parameters were compared between the 2 groups. Results Among 124 patients, 19 had latent TB resulting in a point prevalence of 15.4 %. The average disease duration was 4.3 years in IGRA positive and 4.6 in IGRA negative group(p&gt;0.05). Among antibody profile, though no statistical significance among the groups, proportion of antibodies like anti Ku, Ro 60, Ro 52 and La were numerically higher in the IGRA positive group (21.1%, 42.1%, 42.1% and 21.1% respectively) when compared to the IGRA negative group (11.5%, 28.8%, 28.1% and 7.7% respectively). Likewise, anti nucleosome, histone, U1RNP, PCNA, aCLA IgG and IgM, beta 2 GPI IgG and LAC were numerically higher in IGRA negative group (42.3%, 40.4%, 43.3%, 8.7%, 23%, 18.3%, 28.8%, 14.4%) when compared to IGRA positive group (31.6%, 21.1%, 31.6%, 0, 15.8%, 5.3%, 15.8%, 5.3%). Mean clinical SLEDAI was 2.37 ±5.1 in IGRA positive and 3.5 ±5.77 in IGRA negative group. Among clinical features, 1 person in IGRA positive and none in the IGRA negative group had current gastrointestinal involvement. Comparison of other organ manifestations yielded no statistically significant difference in the 2 groups at this point. Serology revealed greater proportion of C4 in IGRA negative as compared to the positive group(p&lt;0.042). Conclusion Prevalence of latent TB in SLE cases was 15.4%. Although comparison of demographic, clinical and autoantibody profile did not yield any statistically significant differences, the early turnover from this pilot study mandates further evaluation with larger sample size. Table 1. Comparison of clinical and laboratory parameters between IGRA positive and IGRA negative SLE cases IGRA POSITIVE(n=19 ) IGRA NEGATIVE(n=105 ) p VALUE Age(Mean± SD) 31.79±9.7 29.26 ±10.8 0.199 Female Sex n(%) 19(100) 101(97.1) 0.312 Anti P0 antibody n(%) 3(15.8) 14(13.5) 0.827 Anti Ribo P antibody n(%) 2(10.5) 13(12.5) 0.761 Age of disease onset(Mean± SD) 25.58± 10.6 24.62± 10.57 0.285 Disease duration(Mean± SD) 4.33 ±4.02 4.6± 3.53 0.438 Treatment duration(Mean± SD) 3.84± 4.12 4.03± 3.42 0.439 Clinical SLEDAI(Mean± SD) 2.37 ±5.1 3.5 ±5.77 0.306 SLICC ACR DI(Mean± SD) 0.105±0.32 0.231± 0.66 0.666 Current CNS involvement 1(5.3) 4(3.8) 0.781 Current renal involvement 3(15.8) 26(25) 0.367 Current hematological involvement 1(5.3) 14(13.5) 0.272 Current GI involvement 1(5.3) 0 0.052 Current steroid dose(Mean± SD) 11.32± 11.65 13.03 ± 11.6 0.400 Serum C3(Mean± SD) 0.79 ±0.32 0.89± 0.47 0.477 Serum C4(Mean± SD) 0.19± 0.072 0.1635± 0.13 0.413 Anti dsDNA (Mean± SD) 458± 400.8 379.5± 400.5 0.454 Low C3 n(%) 9(52.9) 37(38.9) 0.108 Low C4 n(%) 2(11.8) 35(36.8) 0.042 Elevated Antidsdna n(%) 6(35.3) 37(38.9) 3.343 Disclosure of Interests None declared